Study On The Inhibiton Effect Of Azole Compounds For Copper Corrosion In Synthetic Seawater

Copper is widely used in the fileds of production and daily life because of its good corrosion resistance. However, it will be corroded and damaged remarkedly in the harsh condition, such as, the water full of oxygen (the oxygen rich water), the oxidizing acid solution and solution containing CN- or Cl- ions. While the high concentration of Cl- in seawater causes serious corrosion of copper, which have brought heavy economic losses. In order to inhibit the corrosion of copper, great efforts have been put into the investigation. Among them, inhibitor technology has been the focus of science academy.In this paper, the different inhibitors were investigated in 3.0% NaCl solutions by weight loss and electrochemistry tests. The surface morphology was characterized, and the inhibition mechanism was also discussed.The main research work is as follow:1. Study on corrosion inhibition of copper by 4-amino-antipyrine in 3.0% NaCl solution4-amino-antipyrine (AAP) as the corrosion inhibitor was investigated in 3.0% NaCl solution by electrochemistry tests. Surface observation was performed to ensure the inhibitor adsorbing on the copper surface successfully using scanning electron microscope (SEM) and Fourier transform infrared (FT-IR) spectrometer. The inhibition efficiency of the AAP on copper was about 90.6% according to the data analysis of potentiodynamic polarization and electrochemical impedance spectroscopy curves and showing that the AAP has good protective ability for copper corrosion in 3.0% NaCl solution. The theory parameters of AAP molecule was calculated by quantum chemistry methods, which can provide theoretical support to the experiments. 2. Study on corrosion inhibition of copper by trithiocyanuric acid in 3.0% NaCl solutionTrithiocyanuric acid (TTCA) as an inhibitor was investigated in 3.0% NaCl solution by weight loss and electrochemistry methods. The inhibition efficiency of the TTCA on copper was 95.3% according to the data analysis of potentiodynamic polarization and electrochemical impedance spectroscopy curves and showing that TTCA has good protective ability for copper corrosion. Surface observation was performed to analyse the adsorption on the copper surface using SEM and Energy dispersive X-ray spectroscopy (EDX). The molecular simulation provided the adsorption model of TTCA molecule on the Cu (111) surface. The inhibition mechanism has been study on molecular level.3. Study on corrosion inhibition of copper by 4,6-DimethyI-2-pyrimidinethioI4.6-Dimethyl-2-pyrimidinethiol (DPDT) was investigated by weight loss and electrochemistry methods. The inhibition efficiency of DPDT on copper achieved a value of 78.7% according to the results obtained from the potentiodynamic polarization curves and weight loss. The data of EIS were analyzed to obtain the kinetic parameters of electrode processes by equivalent circuit. Cyclic voltammtry (CV) has been used to certify the effect of inhibitor indirected. Copper surface morphology was characterized by SEM and the conclusion consists with the electrochemical methods and weight loss.